Field studies in West Africa have shown that mormyrid electric fishes have evolved an impressive diversity of electric organ discharges (EODs) which are used in electrolocation and social communication. Field playback experiments indicate that males of at least one species can recognize the EODs of their own species, and will electrically court females, but not other males. Species recognition depends on either the waveform of the EOD pulses, or their repetition rate, and tests with artificial stimuli strongly implicate waveform. Electrophysiological studies of electroreceptors in mormyrids show that they are tuned to species-specific EODs by being frequency selective in the range where the peak power of the Fourier transform of the EOD occurs. Electrophysiological studies are aimed at understanding the mechanisms for the tuning, and at studies of central integration of electroreceptive input.